remove variable name in function declaration

Author: fsaadatmand

chapter02/2-10.c

@@ -1,13 +1,14 @@
 /* 
  * Exercise 2-10. Rewrite the function lower, which converts upper case letters
  * to lower case, with a conditional expression instead of if-else.
+ *
  * By Faisal Saadatmand
  */
 
 #include <stdio.h>
 
 /* functions */
-int lower(char c);
+int lower(char);
 
 /* lower: convert c to lower case; ASCII only */
 int lower(char c)